Technical Guidance Note 24

TOPIC: Bulk eraser for magnetic tapes.

ISSUE: 2

REVISION DATE: 27.1.98

PREVIOUS REVISION DATE: 6.9.95

BACKGROUND: We sell as OEM equipment a bulk eraser for magnetic tapes. The device itself contains a capacitor and a coil and generates a large magnetic field at 50Hz.

PROBLEM: How do we demonstrate compliance to the EMC Directive? Which standards should we assess against?

GUIDELINES: In the absence of any applicable product standards the manufacturer should compile a Technical Construction File.

EN50082-1: 1997 contains a requirement to assess immunity to power frequency magnetic fields at 3A/m. Since the bulk eraser is likely to generate a high magnetic field, the manufacturer should carry out some measurements to determine the distance from the device at which the magnetic field strength is below 3A/m. The Competent Body would ensure that the protection distance was stated in the user manual with clear instructions that apparatus likely to be sensitive to magnetic emissions should not be operated within the stated protection distance from the bulk eraser. The protection distance should be increased for equipment such as CRT monitors.

Disclaimer
No responsibility or liability can be accepted by the EMC Test Laboratories Association or any of its officers or members for the contents, specifications and/or advice referred to or contained in this Technical Memorandum and/or action taken as a result of information contained in this Technical Memorandum. Note that:
1. The Association is not by supplying this Technical Memorandum providing professional advice or guidance to any specific party on any specific matter and no legal relationship is created by the provision of this Technical Memorandum.
2. Parties should take specific advice when dealing with specific situations and consult their own professional advisors in this regard.
3. Members are free to deviate from the above guidelines where they think it appropriate, unworkable, or not commercially viable. Under these circumstances, the EMCTLA Secretariat should be informed of the reasons for the deviation so that the matter can be reviewed.